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The decreased ability of mature oligodendrocytes to produce myelin negatively affects remyelination in demyelinating diseases and aging, but the underlying mechanisms are incompletely understood. In the present study, we identify a mature oligodendrocyte-enriched transcriptional coregulator diabetes- and obesity-related gene (DOR)/tumor protein p53-inducible nuclear protein 2 (TP53INP2), downregulated in demyelinated lesions of donors with multiple sclerosis and in aged oligodendrocyte-lineage cells. Dorablation in mice of both sexes results in defective myelinogenesis and remyelination. Genomic occupancy in oligodendrocytes and transcriptome profiling of the optic nerves of wild-type and Dorconditional knockout mice reveal that DOR and SOX10 co-occupy enhancers of critical myelinogenesis-associated genes including Prr18, encoding an oligodendrocyte-enriched, proline-rich factor. We show that DOR targets regulatory elements of genes responsible for α-ketoglutarate biosynthesis in mature oligodendrocytes and is essential for α-ketoglutarate production and lipid biosynthesis. Supplementation with α-ketoglutarate restores oligodendrocyte-maturation defects in Dor-deficient adult mice and improves remyelination after lysolecithin-induced demyelination and cognitive function in 17-month-old wild-type mice. Our data suggest that activation of α-ketoglutarate metabolism in mature oligodendrocytes can promote myelin production during demyelination and aging.

Extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs) promote neurite outgrowth in culture and enhance peripheral nerve regeneration in rats. This study aimed at expanding the application of SKP-SC-EVs in nerve grafting by creating a chitosan/PLGA-based, SKP-SC-EVs-containing tissue engineered nerve graft (TENG) to bridge a 40-mm long sciatic nerve defect in dogs. SKP-SC-EVs contained in TENGs significantly accelerated the recovery of hind limb motor and electrophysiological functions, supported the outgrowth and myelination of regenerated axons, and alleviated the denervation-induced atrophy of target muscles in dogs. To clarify the underlying molecular mechanism, we observed that SKP-SC-EVs were rich in a variety of miRNAs linked to the axon growth of neurons, and miR-30b-5p was the most important among others. We further noted that miR-30b-5p contained within SKP-SC-EVs exerted nerve regeneration-promoting effects by targeting the Sin3a/HDAC complex and activating the phosphorylation of ERK, STAT3 or CREB. Our findings suggested that SKP-SC-EVs-incorporating TENGs represent a novel type of bioactive material with potential application for peripheral nerve repair in the clinic.

A central question in neural tissue engineering is how the tissue-engineered nerve (TEN) translates detailed transcriptional signals associated with peripheral nerve regeneration into meaningful biological processes. Here, we report a skin-derived precursor-induced Schwann cell (SKP-SC)-mediated chitosan/silk fibroin-fabricated tissue-engineered nerve graft (SKP–SCs-TEN) that can promote sciatic nerve regeneration and functional restoration nearly to the levels achieved by autologous nerve grafts according to behavioral, histological, and electrophysiological evidence. For achieving better effect of neuroregeneration, this is the first time to jointly apply a dynamic perfusion bioreactor and the ascorbic acid to stimulate the SKP-SCs secretion of extracellular matrix (ECM). To overcome the limitation of traditional tissue-engineered nerve grafts, jointly utilizing SKP-SCs and their ECM components were motivated by the thought of prolongating the effect of support cells and their bioactive cues that promote peripheral nerve regeneration. To further explore the regulatory model of gene expression and the related molecular mechanisms involved in tissue engineering-aided peripheral nerve regeneration, we performed a cDNA microarray analysis of gene expression profiling, a comprehensive bioinformatics analysis and a validation study on the grafted segments and dorsal root ganglia tissues. A wealth of transcriptomic and bioinformatics data has revealed complex molecular networks and orchestrated functional regulation that may be responsible for the effects of SKP-SCs-TEN on promoting peripheral nerve regeneration. Our work provides new insights into transcriptomic features and patterns of molecular regulation in nerve functional recovery aided by SKP-SCs-TEN that sheds light on the broader possibilities for novel repair strategies of peripheral nerve injury.

Decellularized extracellular matrix (dECM), with its distinct biological properties, has gained significant attention as a natural biomaterial. Leveraging its potentials, we successfully developed a three-dimensional matrix-based oriented nerve graft by encapsulating a fibrous scaffold with multilayered conformationally intact and biologically active human bone marrow mesenchymal stem cell-derived decellularized extracellular matrix (hBMSC-dECM). Convincingly, the hBMSC-dECM group exhibited comparable functional recoveries to the autograft group by postoperative week 12. In the comprehensive analysis, the molecular regulations in the hBMSC-dECM group were more intricate and nuanced compared to the autograft group. Nevertheless, both groups displayed similar molecular regulatory processes in terms of vascularization and extracellular matrix. Notably, the hBMSC-dECM group demonstrated sustained high levels of regulation in axon and myelin regeneration at week 12, while the immunomodulation returned to the normal levels after peaking at week 2. Collectively, our findings illustrated the satisfactory construction of a cell-matrixed nerve graft that established a microenvironment conducive to nerve regeneration, and elucidated the distinct molecular regulation patterns and characteristics associated with different repair modes.

Tissue regeneration requires exogenous and endogenous signals, and there is increasing evidence that the exogenous microenvironment may play an even more dominant role in the complex process of coordinated multiple cells. The short-distance peripheral nerve showed a spontaneous regenerative phenomenon, which was initiated by the guiding role of macrophages. However, it cannot sufficiently restore long-distance nerve injury by itself. Based on this principle, we firstly constructed a proinflammatory model to prove that abnormal M2 expression reduce the guidance and repair effect of long-distance nerves. Furthermore, a bionic peptide hydrogel scaffold based on self-assembly was developed to envelop M2-derived regenerative cytokines and extracellular vesicles (EVs). The cytokines and EVs were quantified to mimic the guidance and regenerative microenvironment in a direct and mild manner. The bionic scaffold promoted M2 transformation in situ and led to proliferation and migration of Schwann cells, neuron growth and motor function recovery. Meanwhile, the peptide scaffold combined with CX3CL1 recruited more blood-derived M2 macrophages to promote long-distance nerve reconstruction. Overall, we systematically confirmed the important role of M2 in regulating and restoring the injury peripheral nerve. This bionic peptide hydrogel scaffold mimicked and remodeled the local environment for M2 transformation and recruitment, favoring long-distance peripheral nerve regeneration. It can help to explicate regulative effect of M2 may be a cause not just a consequence in nerve repair and tissue integration, which facilitating the development of pro-regenerative biomaterials.

Despite considerable unmet medical needs, effective pharmacological treatments that promote functional recovery after spinal cord injury remain limited. Although multiple pathological events are implicated in spinal cord injuries, the development of a microinvasive pharmacological approach that simultaneously targets the different mechanisms involved in spinal cord injury remains a formidable challenge. Here we report the development of a microinvasive nanodrug delivery system that consists of amphiphilic copolymers responsive to reactive oxygen species and an encapsulated neurotransmitter-conjugated KCC2 agonist. Upon intravenous administration, the nanodrugs enter the injured spinal cord due to a disruption in the blood–spinal cord barrier and disassembly due to damage-triggered reactive oxygen species. The nanodrugs exhibit dual functions in the injured spinal cord: scavenging accumulated reactive oxygen species in the lesion, thereby protecting spared tissues, and facilitating the integration of spared circuits into the host spinal cord through targeted modulation of inhibitory neurons. This microinvasive treatment leads to notable functional recovery in rats with contusive spinal cord injury.

Peripheral nerve injury is a common clinical disease. Effective post-injury nerve repair remains a challenge in neurosurgery, and clinical outcomes are often unsatisfactory, resulting in social and economic burden. Particularly, the repair of long-distance nerve defects remains a challenge. The existing nerve transplantation strategies show limitations, including donor site morbidity and immune rejection issues. The multiple studies have revealed the potential of tissue engineering strategies based on biomaterials in the repair of peripheral nerve injuries. We review the events of regeneration after peripheral nerve injury, evaluates the efficacy of existing nerve grafting strategies, and delves into the progress in the construction and application strategies of different nerve guidance conduits. A spotlight is cast on the materials, technologies, seed cells, and microenvironment within these conduits to facilitate optimal nerve regeneration. Further discussion was conducted on the approve of nerve guidance conduits and potential future research directions. This study anticipates and proposes potential avenues for future research, aiming to refine existing strategies and uncover innovative approaches in biomaterial-based nerve repair. This study endeavors to synthesize the collective insights from the fields of neuroscience, materials science, and regenerative medicine, offering a multifaceted perspective on the role of biomaterials in advancing the frontiers of peripheral nerve injury treatment.

BACKGROUND:: Repair of long-distance peripheral nerve defects remains an important clinical problem. Nerve grafts incorporated with extracellular vesicles (EVs) from various cell types have been developed to bridge peripheral nerve defects. In our previous research, EVs obtained from skin-derived precursor Schwann cells (SKP-SC-EVs) were demonstrated to promote neurite outgrowth in cultured cells and facilitate nerve regeneration in animal studies. METHODS:: To further assess the functions of SKP-SC-EVs in nerve repair, we incorporated SKP-SC-EVs and Matrigel into chitosan nerve conduits (EV-NG) for repairing a 15-mm long-distance sciatic nerve defect in a rat model. Behavioral analysis, electrophysiological recording, histological investigation, molecular analysis, and morphometric assessment were carried out. RESULTS:: The results revealed EV-NG significantly improved motor and sensory function recovery compared with nerve conduits (NG) without EVs incorporation. The outgrowth and myelination of regenerated axons were improved, while the atrophy of target muscles induced by denervation was alleviated after EVs addition. CONCLUSION:: Our data indicated SKP-SC-EVs incorporation into nerve grafts represents a promising method for extended peripheral nerve damage repair.

Although oncolytic adenoviruses are widely studied for their direct oncolytic activity and immunomodulatory role in cancer immunotherapy, the immunosuppressive feedback loop induced by oncolytic adenoviruses remains to be studied. Here, we demonstrate that type V adenovirus (ADV) induces the polarization of tumor-associated macrophages (TAMs) to the M2 phenotype and increases the infiltration of regulatory T cells (Tregs) in the tumor microenvironment (TME). By selectively compensating for these deficiencies, thymosin alpha 1 (Tα1) reprograms “M2-like” TAMs toward an antitumoral phenotype, thereby reprogramming the TME into a state more beneficial for antitumor immunity. Moreover, ADVTα1is constructed by harnessing the merits of all the components for the aforementioned combinatorial therapy. Both exogenously supplied and adenovirus-produced Tα1 orchestrate TAM reprogramming and enhance the antitumor efficacy of ADV via CD8+T cells, showing promising prospects for clinical translation. Our findings provide inspiration for improving oncolytic adenovirus combination therapy and designing oncolytic engineered adenoviruses.

Developing highly efficient advanced battery deionization (BDI) electrode materials at a low cost is vital for seawater desalination. Herein, a high-efficiency wood-based BDI electrode has been fabricated for seawater desalination, benefiting from the self-supporting three-dimensional (3D) nanoporous structure and rich redox-active sites. The finely tuned rich electrochemical redox active C═O groups on the surface of the wood electrode derived from the facile thermochemical conversion of lignin play a crucial role in the Faradaic cation removal dynamics of BDI. Coupling the 3D wood electrode and a polyaniline-modified wood electrode as the cathode and anode, an all-wood-electrode-based deionization battery has been successfully assembled with a state-of-the-art ion removal capacity of up to 164 mg g–1in seawater. Our work reported an example of utilizing wood as the BDI electrode via fine-tuning the redox-active sites, demonstrating a novel resource utilization pathway of converting cheap biomass into BDI electrodes for highly efficient seawater desalination.

Immature dentate granule cells (imGCs) arising from adult hippocampal neurogenesis contribute to plasticity and unique brain functions in rodents1,2and are dysregulated in multiple human neurological disorders3–5. Little is known about the molecular characteristics of adult human hippocampal imGCs, and even their existence is under debate1,6–8. Here we performed single-nucleus RNA sequencing aided by a validated machine learning-based analytic approach to identify imGCs and quantify their abundance in the human hippocampus at different stages across the lifespan. We identified common molecular hallmarks of human imGCs across the lifespan and observed age-dependent transcriptional dynamics in human imGCs that suggest changes in cellular functionality, niche interactions and disease relevance, that differ from those in mice9. We also found a decreased number of imGCs with altered gene expression in Alzheimer's disease. Finally, we demonstrated the capacity for neurogenesis in the adult human hippocampus with the presence of rare dentate granule cell fate-specific proliferating neural progenitors and with cultured surgical specimens. Together, our findings suggest the presence of a substantial number of imGCs in the adult human hippocampus via low-frequency de novo generation and protracted maturation, and our study reveals their molecular properties across the lifespan and in Alzheimer's disease.

Traditional Chinese medicine (TCM) can help prevent or treat diseases; however, there are few studies on the active substances of TCM. For example, Lycium barbarumL. has been proven to be effective in treating osteoporosis for thousands of years, but its active substance remains to be unknown. Prompted by the efforts to modernize TCM, the present study focused on the novel active substance of Lycium barbarumL. to reinforce kidney essence to produce bone marrow. Illumina deep sequencing analysis and stem-loop polymerase chain reaction (PCR) assay revealed that miR162a, a Lycium barbarumL.-derived microRNA, can pass through the gastrointestinal tract to target the bone marrow in mice. Immunofluorescence staining showed that miR162awas absorbed through systemic RNA interference defective transmembrane family member 1 (SIDT1) in the stomach. Bioinformatics prediction and luciferase reporter assay identified that miR162atargeted nuclear receptor corepressor(NcoR). Alizarin red staining and micro-computed tomography (microCT) confirmed that miR162apromoted osteogenic differentiation in bone marrow mesenchymal stem cells, zebrafish, and a mouse model of osteoporosis. In addition, transgenic Nicotiana benthamiana(N. benthamiana) leaves overexpressing miR162awere developed by agrobacterium infiltration method. microCT and tartrate-resistant acid phosphatase staining confirmed that transgenic N. benthamianaleaves effectively protected against osteoporosis in mice. Our study mechanistically explains how Lycium barbarumL. improves osteoporosis and supports that Lycium barbarumL. reinforces kidney essence, thereby strengthening the bone. miR162aexpressed by transgenic plants may represent a novel and safe treatment for human osteoporosis.

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.

It has been shown that material surface topography greatly affects cell attachment, growth, proliferation, and differentiation. However, the underlying molecular mechanisms for cell–material interactions are still not understood well. Here, two kinds of butterfly wings with different surface architectures were employed for addressing such an issue. Papilio ulysses telegonus(P.u.t.) butterfly wing surface is composed of micro/nanoconcaves, whereas Morpho menelaus(M.m.) butterfly wings are decorated with grooves. RSC96 cells grown on M.m. wings showed a regular sorting pattern along with the grooves. On the contrary, the cells seeded on P.u.t. wings exhibited random arrangement. Transcriptome sequencing and bioinformatics analysis revealed that huntingtin (Htt)-regulated lysosome activity is a potential key factor for determining cell growth behavior on M.m. butterfly wings. Gene silence further confirmed this notion. In vivoexperiments showed that the silicone tubes fabricated with M.m. wings markedly facilitate rat sciatic nerve regeneration after injury. Lysosome activity and Htt expression were greatly increased in the M.m. wing-fabricated graft-bridged nerves. Collectively, our data provide a theoretical basis for employing butterfly wings to construct biomimetic nerve grafts and establish Htt lysosome as a crucial regulator for cell–material interactions.

Peripheral nerve defects are a worldwide problem, and autologous nerve transplantation is currently the gold‐standard treatment for them. Tissue‐engineered nerve (TEN) grafts are widely considered promising methods for the same, and have attracted much attention. To improve repair, the incorporation of bionics into TEN grafts has become a focus of research. In this study, a novel bionic TEN graft with a biomimetic structure and composition is designed. For this purpose, a chitin helical scaffold is fabricated by means of mold casting and acetylation using chitosan as the raw material, following which a fibrous membrane is electrospun on the outer layer of the chitin scaffold. The lumen of the structure is filled with human bone mesenchymal stem cell‐derived extracellular matrix and fibers to provide nutrition and topographic guidance, respectively. The prepared TEN graft is then transplanted to bridge 10 mm sciatic nerve defects in rats. Morphological and functional examination shows that the repair effects of the TEN grafts and autografts are similar. The bionic TEN graft described in this study shows great potential for application and offers a new way to repair clinical peripheral nerve defects. In this study, a novel bionic TEN graft is designed. Chitin helical scaffolds are fabricated by mold casting and acetylation. The lumen is filled with hBMSCs–dECM and inner fibers. The effect of bridging the 10‐mm defect of sciatic nerve in rats is similar to that of autograft, which provides a new way to repair clinical peripheral nerve defects.

The extracellular matrix is produced by the resident cells in tissues and organs, and secreted into the surrounding medium to provide biophysical and biochemical support to the surrounding cells due to its content of diverse bioactive molecules. Recently, the extracellular matrix has been used as a promising approach for tissue engineering. Emerging studies demonstrate that extracellular matrix scaffolds are able to create a favorable regenerative microenvironment, promote tissue-specific remodeling, and act as an inductive template for the repair and functional reconstruction of skin, bone, nerve, heart, lung, liver, kidney, small intestine, and other organs. In the current review, we will provide a critical overview of the structure and function of various types of extracellular matrix, the construction of three-dimensional extracellular matrix scaffolds, and their tissue engineering applications, with a focus on translation of these novel tissue engineered products to the clinic. We will also present an outlook on future perspectives of the extracellular matrix in tissue engineering and regenerative medicine.

Transforming growth factor-β (TGF-β) belongs to a group of pleiotropic cytokines that are involved in a variety of biological processes, such as inflammation and immune reactions, cellular phenotype transition, extracellular matrix (ECM) deposition, and epithelial–mesenchymal transition. TGF-β is widely distributed throughout the body, including the nervous system. Following injury to the nervous system, TGF-β regulates the behavior of neurons and glial cells and thus mediates the regenerative process. In the current article, we reviewed the production, activation, as well as the signaling pathway of TGF-β. We also described altered expression patterns of TGF-β in the nervous system after nerve injury and the regulatory effects of TGF-β on nerve repair and regeneration in many aspects, including inflammation and immune response, phenotypic modulation of neural cells, neurite outgrowth, scar formation, and modulation of neurotrophic factors. The diverse biological actions of TGF-β suggest that it may become a potential therapeutic target for the treatment of nerve injury and regeneration.

Tissue engineering is a relatively new but rapidly developing field in the medical sciences. Noncoding RNAs (ncRNAs) are functional RNA molecules without a protein-coding function; they can regulate cellular behavior and change the biological milieu of the tissue. The application of ncRNAs in tissue engineering is starting to attract increasing attention as a means of resolving a large number of unmet healthcare needs, although ncRNA-based approaches have not yet entered clinical practice. In-depth research on the regulation and delivery of ncRNAs may improve their application in tissue engineering. The aim of this review is: to outline essential ncRNAs that are related to tissue engineering for the repair and regeneration of nerve, skin, liver, vascular system, and muscle tissue; to discuss their regulation and delivery; and to anticipate their potential therapeutic applications.

The stiffness and nanotopographical characteristics of the extracellular matrix (ECM) influence numerous developmental, physiological, and pathological processes in vivo. These biophysical cues have therefore been applied to modulate almost all aspects of cell behavior, from cell adhesion and spreading to proliferation and differentiation. Delineation of the biophysical modulation of cell behavior is critical to the rational design of new biomaterials, implants, and medical devices. The effects of stiffness and topographical cues on cell behavior have previously been reviewed, respectively; however, the interwoven effects of stiffness and nanotopographical cues on cell behavior have not been well described, despite similarities in phenotypic manifestations. Herein, we first review the effects of substrate stiffness and nanotopography on cell behavior, and then focus on intracellular transmission of the biophysical signals from integrins to nucleus. Attempts are made to connect extracellular regulation of cell behavior with the biophysical cues. We then discuss the challenges in dissecting the biophysical regulation of cell behavior and in translating the mechanistic understanding of these cues to tissue engineering and regenerative medicine.

Chemical/electric energy-driven processes dominate the traditional precious metal (PM) recovery market. The renewable energy-driven selective PM recycling approach crucial for carbon neutrality is under exploration. Herein, via an interfacial structure engineering approach, coordinational-active pyridine groups are covalently integrated onto the photoactive semiconductor SnS2surface to construct Py-SnS2. Triggered by the preferred coordinational binding force between PMs and pyridine groups, together with the photoreduction capability of SnS2, Py-SnS2shows significantly enhanced selective PM-capturing performance toward Au3+, Pd4+, and Pt4+with recycling capacity up to 1769.84, 1103.72, and 617.61 mg/g for Au3+, Pd4+, and Pt4+, respectively. Further integrating the Py-SnS2membrane into a homemade light-driven flow cell, 96.3% recovery efficiency was achieved for continuous Au recycling from a computer processing unit (CPU) leachate. This study reported a novel strategy to fabricate coordinational bonds triggered photoreductive membranes for continuous PM recovery, which could be expanded to other photocatalysts for broad environmental applications.

MicroRNAs (miRNAs, miRs) are small noncoding RNAs that regulate gene expression at the posttranscriptional level. We have previously identified a group of novel miRNAs in proximal sciatic nerve after sciatic nerve transection by Solexa sequencing, and miR-sc3 is a member of the group. In this study, we aimed to investigate the effects of miR-sc3 on phenotypic modulation of Schwann cells (SCs). miR-sc3 was highly expressed in the injured nerve after sciatic nerve transection. An increased and decreased expression of miR-sc3 promoted and reduced the proliferation and migration of primary SCs, respectively. miR-sc3 directly targeted astrotactin 1 (Astn1) and led to translational suppression of Astn1. There was an inverse association between the time-dependent expressions of miR-sc3 and Astn1 in proximal sciatic nerve after sciatic nerve transection. Overall, miR-sc3 affected SC proliferation and migration by targeting Astn1, thus playing the regulatory role in peripheral nerve regeneration.

The therapeutic benefits of bone marrow mononuclear cells (BM-MNCs) in many diseases have been well established. To advance BM-MNC-based cell therapy into the clinic for peripheral nerve repair, in this study we developed a new design of tissue-engineered nerve grafts (TENGs), which consist of a chitosan/fibroin-based nerve scaffold and BM-MNCs serving as support cells. These TENGs were used for interpositional nerve grafting to bridge a 10-mm-long sciatic nerve defect in rats. Histological and functional assessments after nerve grafting showed that regenerative outcomes achieved by our developed TENGs were better than those achieved by chitosan/silk fibroin scaffolds and were close to those achieved by autologous nerve grafts. In addition, we used green fluorescent protein-labeled BM-MNCs to track the cell location within the chitosan/fibroin-based nerve scaffold and trace the cell fate at an early stage of sciatic nerve regeneration. The result suggested that BM-MNCs could survive at least 2 weeks after nerve grafting, thus helping to gain a preliminary mechanistic insight into the favorable effects of BM-MNCs on axonal regrowth.

The molecular diversity of glia in the human hippocampus and their temporal dynamics over the lifespan remain largely unknown. Here, we performed single-nucleus RNA sequencing to generate a transcriptome atlas of the human hippocampus across the postnatal lifespan. Detailed analyses of astrocytes, oligodendrocyte lineages, and microglia identified subpopulations with distinct molecular signatures and revealed their association with specific physiological functions, age-dependent changes in abundance, and disease relevance. We further characterized spatiotemporal heterogeneity of GFAP-enriched astrocyte subpopulations in the hippocampal formation using immunohistology. Leveraging glial subpopulation classifications as a reference map, we revealed the diversity of glia differentiated from human pluripotent stem cells and identified dysregulated genes and pathological processes in specific glial subpopulations in Alzheimer’s disease (AD). Together, our study significantly extends our understanding of human glial diversity, population dynamics across the postnatal lifespan, and dysregulation in AD and provides a reference atlas for stem-cell-based glial differentiation.

Peripheral nerve functional recovery after nerve injury generally requires multiple growth factors by synergistic effect. However, the optical combination of multiple synergistic growth factors for axonal regeneration has been scarcely considered up to now. Meanwhile, the use of growth factors in promoting nerve regeneration was limited by its short biological half-life in vivo, its vulnerability to structure disruption or hydrolyzation, leading to loss of bioactivity. Herein, a novel polymeric nanoparticle delivery system composed of heparin and ɛ-poly-L-lysine (PL) was prepared for control release of nerve growth factor (NGF) and basic fibroblast growth factor (bFGF). The nanoparticles were synthesized by polyelectrolyte complexation in aqueous solution at room temperature, followed by cross-linking with biological genipin. The obtained nanoparticles had a spherical shape, with a mean diameter of about 246 nm, and high growth factors encapsulation efficiency as well as good stability. NGF and bFGF were encapsulated in the nanoparticles and showed a continuous and slow release behavior in vitro. The bioactivities of the released growth factors were evaluated, and exhibited the synergistic effect. The controlled release of the dual synergistic growth factors would improve the treatment of peripheral nerve injury to mimic the natural cellular microenvironments.

The peripheral nervous system is able to regenerate after injury, and regeneration is associated with the expression of many genes and proteins. MicroRNAs are evolutionarily conserved, small, non-coding RNA molecules that regulate gene expression at the level of translation. In this paper, we focus on the identification and functional annotation of novel microRNAs in the proximal sciatic nerve after rat sciatic nerve transection. Using Solexa sequencing, computational analysis, and quantitative reverse transcription PCR verification, we identified 98 novel microRNAs expressed on days 0, 1, 4, 7, and 14 after nerve transection. Furthermore, we predicted the target genes of these microRNAs and analyzed the biological processes in which they were involved. The identified biological processes were consistent with the known time-frame of peripheral nerve injury and repair. Our data provide an important resource for further study of the role and regulation of microRNAs in peripheral nerve injury and regeneration.

Tissue-engineered nerve grafts (TENGs), typically consisting of a neural scaffold included with support cells and/or growth factors, represent a promising alternative to autologous nerve grafts for surgical repair of large peripheral nerve gaps. Here, we developed a new design of TENGs by introducing bone marrow mesenchymal stem cells (MSCs) of rats, as support cells, into a silk fibroin (SF)-based scaffold, which was composed of an SF nerve guidance conduit and oriented SF filaments as the conduit lumen filler. The biomaterial SF had been tested to possess good biocompatibility and noncytoxicity with MSCs before the TENG was implanted to bridge a 10-mm-long gap in rat sciatic nerve. Functional and histological assessments showed that at 12 weeks after nerve grafting, TENGs yielded an improved outcome of nerve regeneration and functional recovery, which was better than that achieved by SF scaffolds and close to that by autologous nerve grafts. During 1–4 weeks after nerve grafting, MSCs contained in the TENG significantly accelerated axonal growth, displaying a positive reaction to S-100 (a Schwann cell marker). During 1–3 weeks after nerve grafting, MSCs contained in the TENG led to gene expression upregulation of S100 and several growth factors (brain-derived neurotrophic factor, ciliary neurotrophic factor, and basic fibroblast growth factor). These results suggest that the cell behaviors and neurotrophic functions of MSCs might be responsible for their promoting effects on peripheral nerve regeneration.

Bone marrow mesenchymal cells (MSCs) have attracted increasing research interest due to their possible use as support cells for nerve tissue-engineering approaches. We developed a novel design of tissue-engineered nerve grafts consisting of a chitosan/poly(lactic-co-glycolic acid) (PLGA)-based neural scaffold included with autologous MSCs. The graft was used as an alternative to nerve autografts for bridging 50-mm-long gaps in dog sciatic nerve, and the repair outcome at 6 months after nerve grafting was evaluated by a combination of electrophysiological assessment, FluoroGold retrograde tracing, and histological investigation to regenerated nerve tissue and reinnervated target muscle. The experimental results indicated that introduction of autologous MSCs to the chitosan/PLGA-based neural scaffold promoted sciatic nerve regeneration and functional recovery, demonstrating significant efficacy that was, to a certain degree, close to that by nerve autografting, a gold standard for treating large peripheral nerve gaps, and better than that by grafting with the chitosan/PLGA-based scaffold alone.

To find a promising alternative to neurons or schwann cells (SCs) for peripheral nerve repair applications, this study sought to isolate stem cells from fetal rat dorsal root ganglion (DRG) explants. Molecular expression analysis confirmed neural stem cell characteristics of DRG-derived neurospheres in terms of expressing neural stem cell-specific genes and a set of well-defined genes related to stem cell niches and glial fate decision. Under the influence of neurotrophic factors, bFGF and NGF, the neurospheres gave rise to neurofilament-expressing neurons and S100-expressing Schwann cell-like cells by different pathways. This study suggests that a subpopulation of stem cells that reside in DRGs is the progenitor of neurons and glia, which could directly induce the differentiation toward neurons, or SCs.

Visinin-like protein 1 (VILIP-1), a myristoylated calcium sensor protein of the EF-hand Ca2+-binding protein superfamily, plays multiple physiological roles in the central nervous system and peripheral organs. In present study, the cDNA encoding VILIP-1 was identified from the brain and spinal cord cDNA library of Gekko japonicus. It contains a 573 bp open reading frame corresponding to a deduced protein of 191 amino acids. Gecko VILIP-1 shares more than 95.3% identity with vertebrate VILIP-1 proteins, and structurally consists of conserved four EF-hand Ca2+-binding motifs and one dsRNA-binding domain, suggesting that selective pressure must have been extremely high for the conservation of VILIP-1 during vertebrate evolution. Northern blot and RT-PCR showed that gecko VILIP-1 was ubiquitously expressed in all tissues examined. In situ hybridization revealed that the VILIP-1 transcript mainly appeared in the gray matter of the spinal cord, with less distribution in the white matter. Semiquantitative RT-PCR also showed that VILIP-1 expression in spinal cord after tail amputation remained stable at 1 day and 1 week, but decreased at 2 weeks, a time coinciding with regeneration bud formation. This suggests that VILIP-1 may function as a regeneration-associated factor in the form of a monomer or/and RNA-binding complex.

Chitin product was prepared from the chitosan counterpart and both were found to be equally biocompatible with cultured Schwann cells. Chitin‐ and chitosan‐based nerve guidance conduits (NGCs) were surgically implanted to bridge 10‐mm‐long neural defects in rat sciatic nerves. The regenerative outcome provided positive evidence that chitin‐ and chitosan‐based NGCs produce the similar beneficial effects on peripheral nerve regeneration.

Abstract: The human trihydrophobin 1 (TH1) is a highly conserved and widely expressed protein. It is clear that TH1 serves as a new specific negative regulator of A-Raf kinase. In this study, we found that TH1 associated with A-Raf in mouse testis by using coimmunoprecipitation analysis. Then we characterized the gene expression of TH1 in mouse testis and analyzed the changes of TH1 protein during postnatal development. The protein expression of TH1 in mouse testis was further analyzed by immunohistochemistry staining. Strong signals were detected in the seminiferous tubules and the distribution patterns varied with the different ages of postnatal mouse testis. TH1 was distributed in spermatocytes and Sertoli cells at 2 weeks postnatal, and was abundant in spermatogonia at 8 weeks postnatal. Leydig cells were positive to TH1 throughout testicular development. A high expression of TH1 in both Leydig cells and mouse Leydig tumor cells (mLTC-1cells) was found to be concentrated in the cytoplasm. The colocalization of TH1 and A-Raf in mLTC-1 cells or in adult testis was also observable.

Abstract: To have a better insight into the molecular events involved in denervation-induced atrophy and reinnervation-induced regeneration of skeletal muscles, it is important to investigate the changes in expression levels of a great multitude of muscle proteins during the process of denervation–reinnervation. In this study, we employed an experimental model of rat sciatic nerve crush to examine the differentially expressed proteins in the rat gastrocnemius muscle at different time points (0, 1, 2, 3, 4 weeks) after sciatic␣nerve crush by using two-dimensional gel electrophoresis (2-DE) followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS), collectively referred to as the modern proteomic analysis. The results showed that 16 proteins in the rat gastrocnemius muscle exhibited two distinct types of change pattern in their relative abundance: (1) The relative expression levels of 11 proteins (including alpha actin, myosin heavy chain, etc.)were decreased either within 1 or 2 weeks post-sciatic nerve injury, followed by restoration during the ensuing days until 4 weeks. (2) The other 5 proteins (including alpha enolase, beta enolase, signal peptide peptidase-like 3, etc.) displayed an up-regulation in their relative expression levels within 1 week following sciatic nerve injury, and a subsequent gradual decrease in their relative expression levels until 4 weeks. Moreover, the significance of the changes in expression levels of the 16 proteins during denervation–reinnervation has been selectively discussed.

Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily, has been identified as an inhibitor of skeletal muscle mass. To have an insight into the expression pattern of myostatin and its potential role in skeletal muscle atrophy induced by denervation, we used an animal model of peripheral nerve resection to examine the time-dependent changes in myostatin mRNA and protein levels in the denervated gastrocnemius muscle of rats after sciatic neurectomy by the aid of quantitative real-time RT-PCR and Western blotting, respectively. We also conducted morphometric analyses to measure the wet weight ratio of the denervated muscle (the operated side/contralateral non-operated side) and the cross sectional area of muscle fibers and to observe muscle morphology. The experimental results showed that myostatin mRNA and protein levels in rat gastrocnemius muscle persistently elevated after denervation, despite a fluctuation of myostatin mRNA level at day 3 after denervation, reached their respective peaks at day 28 after denervation, and then depressed slightly until day 56 after denervation. Furthermore, a significant negative linear correlation was found between myostatin abundance and muscle atrophy degree, suggesting that myostatin might probably play an important role in denervation-induced muscle atrophy. Our present study perhaps provides a new window into myostatin regulation in association with a specific type of muscle atrophy.Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily, has been identified as an inhibitor of skeletal muscle mass. To have an insight into the expression pattern of myostatin and its potential role in skeletal muscle atrophy induced by denervation, we used an animal model of peripheral nerve resection to examine the time-dependent changes in myostatin mRNA and protein levels in the denervated gastrocnemius muscle of rats after sciatic neurectomy by the aid of quantitative real-time RT-PCR and Western blotting, respectively. We also conducted morphometric analyses to measure the wet weight ratio of the denervated muscle (the operated side/contralateral non-operated side) and the cross sectional area of muscle fibers and to observe muscle morphology. The experimental results showed that myostatin mRNA and protein levels in rat gastrocnemius muscle persistently elevated after denervation, despite a fluctuation of myostatin mRNA level at day 3 after denervation, reached their respective peaks at day 28 after denervation, and then depressed slightly until day 56 after denervation. Furthermore, a significant negative linear correlation was found between myostatin abundance and muscle atrophy degree, suggesting that myostatin might probably play an important role in denervation-induced muscle atrophy. Our present study perhaps provides a new window into myostatin regulation in association with a specific type of muscle atrophy.

We have developed a dual-component artificial nerve graft comprising an outer microporous conduit of chitosan and internal oriented filaments of polyglycolic acid (PGA). The novel graft was used for bridging sciatic nerve across a 30-mm defect in six Beagle dogs, which were used as a chitosan/PGA graft group. The other Beagle dogs were divided into an autograft group (n = 6) as the positive control and a non-grafted group (n = 5) as the negative control. All animals of three groups were monitored for changes in their appearance and locomotion activities after surgery. Their posture and gait were recorded regularly with the aid of photographs and videotapes for each dog. Six months post-operatively, a combination of electrophysiological examination, FluoroGold retrograde tracing, histological assessment including light microscopy and transmission electron microscopy, immunohistochemistry as well as morphometric analyses to both regenerated nerves and target muscles was utilized to investigate the nerve repair effects of our artificial nerve graft. The results demonstrated that, in the chitosan/PGA graft group, the dog sciatic nerve trunk had been reconstructed with restoration of nerve continuity and functional recovery, and its target skeletal muscle had been re-innervated, improving locomotion activities of the operated limb. This study proves the feasibility of the chitosan/PGA artificial nerve graft for peripheral nerve regeneration by bridging a longer defect in a large animal model.

Following severe spinal cord injury (SCI), dysregulated neuroinflammation causes neuronal and glial apoptosis, resulting in scar and cystic cavity formation during wound healing and ultimately the formation of an atrophic microenvironment that inhibits nerve regrowth. Because of this complex and dynamic pathophysiology, a systemic solution for scar‐ and cavity‐free wound healing with microenvironment remodeling to promote nerve regrowth has rarely been explored. A one‐step solution is proposed through a self‐assembling, multifunctional hydrogel depot that punctually releases the anti‐inflammatory drug methylprednisolone sodium succinate (MPSS) and growth factors (GFs) locally according to pathophysiology to repair severe SCI. Synergistically releasing the anti‐inflammatory drug MPSS and GFs in the hydrogel depot throughout SCI pathophysiology protects spared tissues/axons from secondary injury, promotes scar boundary‐ and cavity‐free wound healing, and results in permissive bridges for remarkable axonal regrowth. Behavioral and electrophysiological studies indicate that remnants of spared axons, not regenerating axons, mediate functional recovery, strongly suggesting that additional interventions are still required to render the rebuilt neuronal circuits functional. These findings pave the way for the development of a systemic solution to treat acute SCI. A one‐step solution is proposed through a self‐assembling, multifunctional hydrogel depot to repair severely damaged spinal cord. The hydrogel depot treatment protects spared tissues/axons from secondary injury, promoted scar boundary‐ and cavity‐free wound healing, and results in remarkable axonal regrowth and robust functional recovery.

Objectives To characterize differences in cardiac structure and function in hemodialysis (HD) patients with diabetic nephropathy (DN) and in those without using echocardiography and to determine their impact on the prediction of mortality using echocardiographic parameters.Methods Clinical, laboratory, and echocardiographic data were collected from patients commencing HD.Results Compared with those without DN, patients with DN had lower peak velocity of the early diastolic wave (e′), larger left atria, and higher peak early diastolic velocity (E)/e′ and peak velocity of tricuspid regurgitation (TR). In addition, a larger proportion of DN patients had a combination of left ventricular (LV) diastolic dysfunction, cardiac valve calcification, moderate-to-severe cardiac valve regurgitation (CVR), and at least moderate pericardial effusion (PE). After accounting for age, sex, smoking, hypertension, hemoglobin, and albumin, DN was responsible for e′  < 10 cm/s, E/e′ >13 m/s, TR >2.8 m/s, LV diastolic dysfunction, CVR, and PE. LV diastolic dysfunction and E/e′ >13 were the most useful predictors of mortality in patients with DN.Conclusions Patients with DN who undergo HD tend to have worse LV diastolic function and are more likely to have heart valve problems. LV diastolic dysfunction and E/e′ are predictors of death in DN patients.

The molecular network features of spinal cord development that are integral to tissue engineering remain poorly understood in placental mammals, especially in terms of their relationships with vital biological processes such as regeneration. Here, using a large-scale temporal transcriptomic analysis of rat spinal cord from the embryonic stage to adulthood, we show that fluctuating RNA expression levels reflect highly active transcriptional regulation, which may initiate spinal cord patterning. We also demonstrate that microRNAs (miRNAs) and transcriptional factors exhibit a mosaic profile based on their expression patterns, while differential alternative splicing events reveal that alternative splicing may be a driving force for the development of the node of Ranvier. Our study also supports the existence of a negative correlation between innate immunity and intrinsic growth capacity. Epigenetic modifications appear to perform their respective regulatory functions at different stages of development, while guanine nucleotide-binding protein (G protein)-coupled receptors (including olfactory receptors (ORs)) may perform pleiotropic roles in axonal growth. This study provides a valuable resource for investigating spinal cord development and complements the increasing number of single-cell datasets. These findings also provide a genetic basis for the development of novel tissue engineering strategies.

Spinal cord injury (SCI) often leads to permanent disability, which is mainly caused by the loss of functional recovery. In this review, we aimed to investigate why the healing process is interrupted. One of the reasons for this interruption is the formation of a glial scar around the severely damaged tissue, which is usually covered by reactive glia, macrophages and fibroblasts. Aiming to clarify this issue, we summarize the latest research findings pertaining to scar formation, tissue repair, and the divergent roles of blood-derived monocytes/macrophages, ependymal cells, fibroblasts, microglia, oligodendrocyte progenitor cells (OPCs), neuron-glial antigen 2 (NG2) and astrocytes during the process of scar formation, and further analyse the contribution of these cells to scar formation. In addition, we recapitulate the development of therapeutic treatments targeting glial scar components. Altogether, we aim to present a comprehensive decoding of the glial scar and explore potential therapeutic strategies for improving functional recovery after SCI.

Human brain organoids provide unique platforms for modeling development and diseases by recapitulating the architecture of the embryonic brain. However, current organoid methods are limited by interior hypoxia and cell death due to insufficient surface diffusion, preventing generation of architecture resembling late developmental stages. Here, we report the sliced neocortical organoid (SNO) system, which bypasses the diffusion limit to prevent cell death over long-term cultures. This method leads to sustained neurogenesis and formation of an expanded cortical plate that establishes distinct upper and deep cortical layers for neurons and astrocytes, resembling the third trimester embryonic human neocortex. Using the SNO system, we further identify a critical role of WNT/β-catenin signaling in regulating human cortical neuron subtype fate specification, which is disrupted by a psychiatric-disorder-associated genetic mutation in patient induced pluripotent stem cell (iPSC)-derived SNOs. These results demonstrate the utility of SNOs for investigating previously inaccessible human-specific, late-stage cortical development and disease-relevant mechanisms.

Introduction:Breath training has been proposed as a new non-pharmacological treatment with potential to induce favorable effects in patients with myocardial infarction However, no information is available regarding its effects on quality of life in these patientsHypothesis:We hyothesis breath training can increase heart function and improve quality of life in patients after myocardial infarction.Methods:Between 2016-2018, 136 acute myocardial infarction patients who received percutaneous coronary intervention were enrolled in our study. 24 hour later after percutaneous coronary intervention, patients were randomly divided into two groups: Control group (n=60) received usual care; Breath training group ( n=76) began with usual care, followed by breath training. Patients undergoing breathing training were asked to perform two separate 15 min sessions per day, at a breathing frequency of 6 breaths/min. Blood pressure, echocardiography, and other clinical parameters were collected before and after patient enrollment. QoL was assessed at the beginning and after 4 week using the MacNew Heart Disease Health-related Quality of Life questionnaire.Results:There were no significant differences in patient characteristics between these groups at baseline. After 4 week of training, there were no significant differences in systolic blood pressure and diastolic blood pressure between the groups, but heart rate was lower in breath training group compared to control (72.42?7.14 vs 80.71?8.53), and breath training group had lower Rate-pressure Product (RPP) (9133.21?1107.69 vs 11272.65?1968.21) compared with control. After 4 week of training after percutaneous coronary intervention and pharmacologic therapy, both groups experienced significant increases in left ventricular ejection fraction (LVEF). Moreover, breath training group had higher LVEF (50?5.53 vs 44+4.22) and higher life quality (86.95?12.73 vs 72.47?13.60) than control.Conclusions:Our data indicate that breath training improves cardiac function and Quality of Life in patients after myocardial infarction. Breath training may serve as a novel component of non-pharmacological primary therapy in after myocardial infarction.